In the keen football mind of Sir Alex Ferguson, referees obviously find themselves embroiled in an ongoing score chart of debts owed and repaid. Yesterday, Rob Styles repaid a huge one to Manchester United with an outlandish penalty decision that put the defending champions on course for their first home league win of the season.

Styles pointed to the spot, to the apparent disbelief of more than 75,000 witnesses, just before the hour when Cristiano Ronaldo's darting run into the Bolton area was concluded by a superbly-timed and legitimate tackle from Jlloyd Samuel.

After Ronaldo calmly stroked home the penalty, the reaction of Bolton manager Gary Megson was one of predictable outrage. For Ferguson, Styles has merely paid back one of his 'debts'.

'I was surprised,' said Ferguson of the decision. 'I haven't seen it again but it looked to me as if their player got his foot on the ball. None the less, Rob turned down four or five for us last year, so maybe we got payback today - but he still owes us four!

'We would have won the game OK, but when teams are defending the way they did, with that determination, they are difficult to break down and you need a little break like that."

Despite Styles' aberration, United were full value for a victory that was assured when substitute Wayne Rooney responded to his manager's new squad rotation policy by stroking in a superb second goal, six minutes after coming on as a 71st minute replacement.

But, naturally, the fact that Rooney stretched United's advantage - and that fellow substitutes Nani and Paul Scholes, twice, should have stretched it further in the final 10 minutes - could not placate Megson. 'I can't imagine there is any side in the world where you have to play against the likes of Berbatov, Ronaldo, Tevez and Rooney and yet it was 0-0,' said Megson. 'Unfortunately, you can add Rob Styles to those four.

'It wasn't a penalty. At the time when it was given, I didn't think it was even close and he was contemplating booking Ronaldo for diving and that would have been wrong. It was a nonsense decision.

'It sticks in the throat that last season, people were talking about diving, feigning injury and technology to help referees with goal-line and penalty incidents and what do we come up with? Respect for the referee, which is quite ironic.

'When we found out he was refereeing the game on Thursday, apparently he's got a bit of a history with Bolton and quite a few hearts sank.'

For all his justified outrage, Megson will know that his team had ridden their luck before Styles' decision. Jussi Jaaskelainen made a sharp early save to keep out Dimitar Berbatov's header, but then spilled Carlos Tevez's long shot and watched Park Ji-Sung turn the rebound into the side-netting from a tight angle.

Two firm Ronaldo free-kicks were well held by the keeper. Anderson and Rio Ferdinand were unmarked in the area but missed before Bolton, bizarrely, missed the best chance of the first half from Gretar Steinsson's right-wing cross.

Kevin Davies and Ferdinand slid in together, but missed the ball and the unmarked Fabrice Muamba had the apparently simple task of converting from a dozen yards, only to miscue his shot horribly, sending the ball well wide.

Ricardo Gardner had a glimpse of the United goal soon after the restart but the home side did not need long to re-apply the pressure. A Neville cross was mis-kicked by O'Brien and collected by Ronaldo, whose cheeky, prodded shot found a path through a crowded area and struck the foot of the post.

If there was misfortune in that incident, Styles soon repaid United, although there was no luck, only quality, about United's second goal, when Ronaldo linked with Rooney, who steadied himself, checked into space and placed an unstoppable shot beyond the dive of Jaaskelainen.THE FANS' PLAYER RATINGS AND VERDICT

I was sure we were going to win beforehand, but it was beginning to look that we wouldn't the longer the game went on. The thing about the penalty is, if you keep on attacking you get more chances and I thought it was a fair reward. The decision looked right to me, anyway. Then Rooney came on and he always looks like he's going to score to me - it was really pleasing to see him get his first league goal of the season. We've hardly got going in the league this year, with all the cup competitions going on, but I'm sure we'll go on from here.The fan's player ratings Van der Sar 7; Neville 6, Ferdinand 8, Vidic 7, Evra 8; Ronaldo 7 (Nani 6), Fletcher 7, Anderson 7 (Scholes 6), Park 6; Tevez 8 (Rooney 8), Berbatov 7

It was disappointing, the penalty seemed to turn things. We looked good defensively but it's just a shame we have to get eight men behind the ball to do it. The penalty was really suspect but United were the better team and I think they'd have won anyway. We've just got nothing in the final third - we had two decent opportunities and I think they were about the only two times we tried to get forward. We had other chances to press, but no one looked interested and it's been like that all season. We were playing Elmander up front on his own and that's just not going to do the job. But we're stuck with this team until Christmas now, so we'll have to make the best of it.